BACKGROUND:
Previous research indicates that pregnancy marital relationship predicts early parental bonding (up to 4 months). However, its long-term influence and evolving predictors beyond one year remain largely unclear. Understanding these complex dynamics is crucial for effective parental support.

OBJECTIVES:
This study aimed to clarify pregnancy marital relationship's role in parental bonding (0-3 years) and identify other dynamic predictors for both parents.

METHODS:
A longitudinal cohort comprising 139 couples was followed at nine time points from pregnancy to three years postpartum. Measures included Quality Marriage Index, Mother-Infant Bonding Questionnaire, Edinburgh Postnatal Depression Scale, and additional questions on parenting status, meticulously collected. Hierarchical multiple regression was performed, and bonding predictors identified (p < 0.05).

RESULTS:
Pregnancy marital relationship predicted early bonding (up to 4 months) but its predictive power did not extend beyond one year. Bonding (1-3 years) was predicted by various factors (R² ranging from 0.113 to 0.457, with p-values from 0.001 to 0.005). Key predictors varied by parent's sex and child's age, including marital relationship (p= 0.001-0.043), depression, and infant sex. No significant maternal predictors were found at 3 years. Trends showed declining marital relationships and diverging bonding trajectories.

CONCLUSIONS:
Pregnancy marital relationship is crucial for early bonding, but its direct influence diminishes after one year. This is likely because bonding factors become more diverse and evolve with child development. Lack of 3-year maternal predictors and diverging trajectories highlight bonding's complexity, suggesting qualitative evolution and challenging the efficacy of static measures. Findings underscore dynamic nature of parental bonding over time. Our study provides novel insights into complex longitudinal patterns.

KEY MESSAGE:
To promote optimal bonding during pregnancy and early postpartum, supporting a good marital relationship is essential. Beyond one year, a multifaceted, individualized approach is crucial, considering evolving family dynamics, child development, parental mental health, and diverse support systems. Timely and effective midwifery care is vital. Poster session 2 (Group A)